6G 
ter, he does not consider it so foreign to the nature 
of vegetables as to derange their functions. Many 
plants, he observes, will vegetate a long time, al- 
though covered entirely with water, and aquatic 
plants live continually in it. In fact, the water, ac- 
cording to him, only intercepts the communication be- 
tween the plant and the atmosphere ; and though it 
prevents the plant from receiving any thing from the 
air, it does not put any obstacle to the discharge of 
what it contains *. 
294. These ideas may, to a certain extent, be cor- 
rect. M. Bonnet has shewn that the leaves of vari 
ous plants, when separated from their branches, con- 
tinue fresh several weeks, and, in some instances, 
even months, when their surfaces are laid on water. 
In some cases, the experiment succeeded best when 
the upper surface of the leaf, and in others, when 
the under surface, was applied to the water f. It may 
be doubted, however, whether leaves continue fresh 
so long when they are completely immersed, since 
the means of evaporation are then cut off, and con- 
sequently the water received must remain stagnant 
in the leaf. In the greater number of Dr Ingen- 
housz's experiments, however, the process continued 
only a few hours, and the leaves, therefore, though 
unable to vegetate, may be still considered as pos- 
sessing life. 
295. The employment of water is farther objection- 
able* because it not only removes the vegetable from. 
* Exper. t. i. sec. 8. p. 43. 
jr Recherches sur lUsage des Feuilles, p. 8. 
